A 69-year-old male was evaluated for complaints of dyspnoea. Transthoracic echocardiography showed a moderate left ventricular systolic function. Although a significant aortic regurgitation was suspected, the valves could not be evaluated properly due to poor image quality. Consequently, transoesophageal echocardiography was performed which revealed a quadricuspid aortic valve (Fig. 1a and b). Only a moderate central aortic regurgitation was observed, valvular replacement was not indicated at the time. The ventricular dysfunction was found to be ischaemic of origin, the patient was treated successfully by percutaneous coronary intervention. Malformation of the semilunar valves is the most common congenital anomaly involving the heart. Bicuspid aortic valve affects the general population in approximately 2%. A quadricuspid aortic valve has an estimated incidence of only 0.008% to 0.043% [1]. It frequently results in progressive aortic regurgitation. In 114 reported cases, 46 patients underwent surgery during follow-up [2]. Therefore, an accurate diagnosis is important.